This application relates to optical fibers and fiber devices with one or more fibers engaged and aligned on substrates.
Optical fibers can be used to transmit or process light in a variety of applications, including delivering light to or receiving light from integrated optical components or devices formed on substrates, transmitting information channels in wavelength-division multiplexed optical communication devices and systems, forming fiber optic switch matrix devices or fiber array to array connector, and producing optical gain for optical amplification or laser oscillation. In some applications, it is desirable to place one or more fibers on a substrate, such as a semiconductor substrate.
For example, in an array waveguide grating (AWG) or wavelength grating router (WGR), input and output dielectric waveguides are usually formed over a silicon substrate to, e.g., direct received WDM channels to designated output waveguides, or to simultaneously receive different input signals at the same optical carrier wavelength to different input ports of the waveguides. Typically, such multi-channel AWG systems can be fabricated by silica-on-silicon technique in which each waveguide is formed of a high-index silicon compound core sandwiched between two cladding layers formed from a low-index silicon compound. This waveguide structure is fabricated over a crystal silicon substrate. Silicon dioxide compounds may be used to form the waveguide core and the cladding layers. When used in a fiber optic system, an AWG device is interfaced with optical fibers. The fibers are generally bonded to either the same silicon substrate on which the AWG is formed or a separate silicon substrate and are then coupled to the waveguides in a pigtail configuration.
The present disclosure includes structures that integrate one or more fibers to a substrate whose material properties match, or are similar to, the properties of the fiber. Hence, when properly engaged, the integrated fiber and the substrate respond similarly to the environmental changes. As a result, the structure is relatively stable. Special techniques are also provided to use an alignment template formed of a material such as silicon for precisely aligning the fibers on the substrate and for fabricating the structures.